The U.S.LHC Tier-1 and Tier-2 laboratories and universities are developing production Grids to support LHC applications running across a worldwide Grid computing system. Together with partners in computer science, physics grid projects and running experiments, we will build a common national production grid infrastructure which is open in its
architecture, implementation and use.

The OSG model builds upon the successful approach of last year's joint Grid2003 project. The Grid3 shared nfrastructure has for over eight months given significant computational resources and throughput to more than six applications, including ATLAS and CMS data challenges, SDSS, LIGO and Biology analyses and computer science demonstrators.

To move towards LHC-scale data management, access and analysis capabilities, we will need to increase the scale, services, and sustainability of the current infrastructure by an order of magnitude.
This requires a significant upgrade in its functionalities and technologies.

The OSG roadmap is a strategy and work plan to build the U.S.LHC computing enterprise as a fully usable, sustainable and robust grid, which is part of the LHC global computing infrastructure and open to partners. The approach is to federate with other application communities in the U.S. to build a shared infrastructure open to other sciences and capable of being modified and improved to respond to needs
of other applications, including CDF, D0, BaBar and RHIC experiments.

We describe the application driven engineered services of the OSG, short term plans and status, and the roadmap for a consortium, its partnerships and national focus.